88 Johnson 3-cyl timing

[subfixer]

I'm attempting timing checks via the SELOC manual. Their procedure measures the piston location with the timing pointer at the 12 TDC position and then again when the piston returns to that position after rotating the flywheel CCW. Splitting the distance between those marks is supposed to identify the TDC location. It then tells me to move the timing pointer to that position. Problem is the new TDC mark is far more than the pointer adjustment will allow. What am I doing wrong? Also when I do a timing light check at idle speed, it shows that I am timed at about TDC -3, rotating the throttle rod doesn't seem to change the timing position. Appreciate any insights.......

 

[retiredfornow]

Re: 88 Johnson 3-cyl timing

Go to the Top Secret file and use the timing found there for WOT timing. I just used that for my '88 60hp Evinrude and it worked great. As far as the TDC mark, you must be doing something wrong. The pointer was probably right to begin with, mine was anyway. What are using for a piston locater?

 

[subfixer]

Re: 88 Johnson 3-cyl timing

thx..I'll try that procedure. I used a mechanical depth gauge through the spark plug hole.

 

[AEROCOOK]

Re: 88 Johnson 3-cyl timing

thx..I'll try that procedure. I used a mechanical depth gauge through the spark plug hole.

I used a NGK BR9ES spark plug from my snowmobile. Its a longer plug and the piston will contact it when you rotate the crank.

 

[subfixer]

Re: 88 Johnson 3-cyl timing

I am not sure what part of the pointer adj. procedure that I am doing wrong. The piston is at it's top position at the 12 BTDC mark on the flywheel. After rotating the flywheel CCW it returns to it's top position at approx. 12 ATDC. Dividing the two marks puts the 0 position at the TDC mark already embossed on the flywheel. Without any other instruction to move the flywheel, the procedure says to loosen and position the timing pointer to that 0 TDC flywheel mark. The actual flywheel and piston is still at the 12 ATDC position however. There simply isn't enough adjustment of the timing pointer that would allow it to move to the 0 TDC mark. And it doesn't seem correct to move the pointer to 0 while the piston is actually at 12 ATDC. Since all timing depends upon an accurate pointer location, I need to get this right.
Does the Joe Reeves WOT timing procedure require a spark tester on all 3 plugs or just the #1 cyl.? If just #1 should #2 & 3 be grounded?

 

[retiredfornow]

Re: 88 Johnson 3-cyl timing

Once you mark the before and after, half way between these 2 points is the point where the piston is at TDC, and at that halfway point is where your pointer should be pointing at.
That long reach plug is a great idea that AEROCOOK has!
Use the spark tester on the #1 plug and ground out the other 2.
I don't know if I cleared anything up for you. Maybe someone else can explain it better. Good Luck.

 

[subfixer]

Re: 88 Johnson 3-cyl timing

I am feeling really dense. If the piston is at the top of it's travel at both the +12 and at the - 12 flywheel marks, how can it be at TDC half way between those marks? And ....after marking the midway point, where should the flywheel (and the piston) be when I adjust the pointer to that midway mark?

 

[retiredfornow]

Re: 88 Johnson 3-cyl timing

The piston at +12 is on it's way to being at Top Dead Center. The piston at -12 is past it's way from being at TDC. At +12 and at -12, the piston is equidistant from being at TDC. If you measure between these 2 points, along the circumference of the flywheel, halfway will be where the piston will actually be at TDC. This halfway mark is where the pointer should be adjusted to.
In other words the piston is NOT at TDC at +12 and -12.
I hope I've been some help. Good luck.

 

[subfixer]

Re: 88 Johnson 3-cyl timing

retiredfornow........thx for your help and patience. I am sure you are correct and I am misunderstanding this procedure. When I measure the piston position, through the spark plug hole, it is at it's top travel at the +12 & -12 positions. It is lower in the cylinder when I rotate it to the midway position, between those +12 & -12 marks. Nonetheless, If the new midway point is different than the the current cast-in TDC mark on the flywheel, should I turn the flywheel to that cast-in mark and then adjust the pointer to the new midway point?
Again...thx and stay healthy (and retired)

 

[retiredfornow]

Re: 88 Johnson 3-cyl timing

Ok, let's try it this way. Forget about 12 and 12. Rotate the flywheel clockwise until the TDC mark is near the pointer. Using your depth guage loosely, check the piston position, and rock the flywheel back and forth, just a little, and you'll be able to tell the approx. TDC of the piston. Note approx. where this is on the flywheel. Now, back off your depth guage, rotate the flywheel clockwise just a little until you can feel the piston going down with the depth guage. Stop and make a reference mark, a little scratch on the flywheel, where the pointer points to, and read your depth guage. This is "X" after top dead center. Now rotate the flywheel clockwise, bringing it around slowly toward, but not at, your previous mark, and stop when the piston hits the depth guage, with the depth guage set at the previous depth for "X". Make a scratch mark on the flywheel where your pointer is pointing, and this will be "Y" before Top Dead Center. Now measure along the flywheel between X and Y and make a mark halfway. Betcha it lines up with the TDC mark on your flywheel. Now, loosen and move the pointer to the TDC mark.
If anyone reads this and I am wrong somewhere, jump in and let's help subfixer out. Good luck.

 

[subfixer]

Re: 88 Johnson 3-cyl timing

thx again, I'll give this a try.